source: rtems/cpukit/libpci/pci_access_func.c @ 71e8a5c

/*  PCI Access Library
 *
 *  COPYRIGHT (c) 2010 Cobham Gaisler AB.
 *
 *  The license and distribution terms for this file may be
 *  found in the file LICENSE in this distribution or at
 *  http://www.rtems.com/license/LICENSE.
 */

#include <pci.h>

/* Get PCI I/O or Configuration space access function */
static int pci_ioc_func(int wr, int size, void **func, void **ops)
{
        int ofs;

        ofs = 0;
        if (wr)
                ofs += 3;
        if (size == 4)
                size = 3;
        ofs += (size & 0x3) - 1;
        if (ops[ofs] == NULL)
                return -1;
        if (func)
                *func = ops[ofs];
        return 0;
}

/* Get Registers-over-Memory Space access function */
static int pci_memreg_func(int wr, int size, void **func, int endian)
{
        void **ops;
        int ofs = 0;

        ops = (void **)pci_access_ops.memreg;
        if (!ops)
                return -1;

        if (size == 2)
                ofs += 2;
        else if (size == 4)
                ofs += 6;

        if (size != 1 && endian == PCI_BIG_ENDIAN)
                ofs += 2;

        if (wr)
                ofs += 1;

        if (ops[ofs] == NULL)
                return -1;
        if (func)
                *func = ops[ofs];
        return 0;
}

/* Get function pointer from Host/BSP driver definitions */
int pci_access_func(int wr, int size, void **func, int endian, int type)
{
        switch (type) {
        default:
        case 2: /* Memory Space - not implemented */
                return -1;
        case 1: /* I/O space */
                return pci_ioc_func(wr, size, func, (void**)&pci_access_ops.cfg);
        case 3: /* Registers over Memory space */
                return pci_memreg_func(wr, size, func, endian);
        case 4: /* Configuration space */
                return pci_ioc_func(wr, size, func, (void**)&pci_access_ops.io);
        }
}